Oven-thermometer



(No Model.)

D. G. COOPER'.

OVEN THERMOMETER.

Patented Apr. 1 2, 1887.

51A/menton N. PETERS. Piwilhaguphur. WzeNnglon, 04@

NITED STATES PATENT OFFICE.

DAVIDYG. COOPER, OF DOVER, NEW HAMPSHIRE.

OVEN-THERMOMETER.

SPECIFICATION forming part of Letters Patent No. 360,950, dated April12, 1887.

Application filled August 12, 1886. Serial No. 210,731.

.To ctZZ whom it may concern.:

Be it known that I, DAvIn G. COOPER, a citizen of the United States,residing at Dover, in the county of Stratford and State of NewHampshire, have invented certain new and useful Improvements inOven-Thermometers, and I do declare the following to be avfull, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, and to the letters andfigures of reference marked thereon, which form a part of thisspec-ication.

Thisinvention relates to devices for indicat` ing and measuring the heatof an oven, kiln, or similar heating surface or chamber, the objectbeing lto provide a compact and convenient device that may be readilyapplied to the door or other part of a stove, a range, oven, duc., andto those heaters that are already in use as well as those to behereinafter manufactured.

In the annexed drawings, illustrating my invention, Figure l is a planview of my improved pyrometer mechanism. Fig. 2 is a side view of thepyrometer-casing in position, with the dial-case and a portion of thestove and oven in section. Fig. 3 is a similar view of the same partsdifferently arranged. Fig. 4 is a face view of the dial andindex-finger.

Like letters of reference designate like parts in all the figures.

A represents the thermometercasing, made, preferably, in the circularform shown; but it may, obviously, if so desired, be constructed in anyother convenient shape and size. Within the casing A, which ispreferably made of cast-iron, are lugs a a, ysecured to or cast integralwith the case, which serve as crease in temperature, but in a differentratio' uides for the expansible metallic bars B B B B, that aregenerally made of brass or some metal that readily expands with anyinfrom the expansion of the casing. Arranged at right angleswith theexpansible bars B B' B B are pivoted the multiplying-levers C, C', C, C,and 0*. The lever C* is pivoted to the end of a connecting link or rod,D, the opposite end of which is attached to the segment-gear E, thatmeshes with a pinion, F, on the shaft G, which carries the index fingeror pointer H.

(No model.)

It will thus be seen how efficient will be the operation of this compactseries of bars and levers in actuating the dial-finger when heat causesan expansion or lengthening of the bars,A for the said bars and leversare combined and arranged within the casing A in a manner designed toaccomplish the most successful results; The bar B bears endwise againstone end of the lever C, which is at right angles thereto, and theopposite end of the lever C 'abuts against the bar B'. The other end ofbar B touches and acts upon the pivoted lever C', Whose other extremityis in contact with the expansion-bar B, located parallel to and betweenbars B and B. The lever C is pivoted alongside of the lever C,

and its ends are respectively in Contact with the bars B and B. The barB presses against the end of the lever C', the opposite end of whichlever is formed with a lug or equivalent projecting knob, so that it mayreadily bear against the long lever O1, pivoted at one end tothe casing,as shown, and at the other to the connecting-link D, which is attachedto the pivoted segment E, and will move the latter and thus rotate thepinion F, and thereby change the position of the indexfinger. Theexpansion of the bars by this train of devices therefore accomplishesthe result of moving the index-finger and of indicating upon the dialthe degree of heat attained by the oven with which theV pyrometer isused. Through the casing A is inserted an adjustingscrew, b, the innerend of which bears against the end of the expansible bar B. By turningthis screw the series of bars and multiplyinglevers, Src., are movedsufficiently to adjust the index-finger H as may be required.

I represents the cover of the thermometercasing A. 'lhis cover issecured to the casing by the screws c, or other equivalent means. Theoven-door to which the pyrometer is attached is designated J. The modeof attachment to said door will differ with different heating devices.One plan is shown in Fig.

2 'and another in Fig. 3. The shaft G, that carries the pinion F andindex-nger H, may be of any required length, and is preferably inclosedin a tube, K,which is cast as apart of or is secured to the cover Landpassed through an opening in the door J, or else said shaft may bepassed directly through an opening in cover I,

ICC

as shown in Fig. 2, the one plan or the other being used, according asthe one or the other Inode of attachment of the pyrometer is adopted.The tube or projection K, and also the shaft G, may be cut oft' at orextended to any desirable length, which will thus adapt the device foruse with old heating arrangements.

In Fig. 2 the cover' I forms the bottom of the dial-ease, the sidesthereof being lettered L, which sides are rabbeted, as shown, for thepurpose of upholding the tlial-faee,w'l1ich may be graduated similar toa clock-dial, and be provided with niarksindicating degrees of heat andthe temperature at which various articles of food should be cooked. Atransparent cover, M, is attached over the dial-face and index-finger bymeans of ametallie rim or band, N, as shown in Figs. 2 and 3.

In Fig. 2 the casing A is properly secured to the door by means ofscrews orother means, and enough of the door is cut away to receive thedial-case in the opening thus aiforded.

In Fig. 3 the door is only pierced for the reception of the spindletubeK and the long attaching-screws d, that pass between the dialcase andpyrometer-mechanism casing, the door remaining otherwise intact. In theinterspaces between the door and the two casiu gs are located layers ofasbestus e c, which serve the double purposeof preventing heat frompassing to the dial-case and also of preventing the seeuringscrews d dfrom being looscned, the elasticity of the asbestus being a safeguard inthis respect. In addition to the asbestus layers, metallic layers orwashers f f are inserted between the layers of asbestus,to strengthenthe device when the distances between the door and the casings isconsidera ble.

Vhen the expansion-bars are cooled by the ,reduction in the temperatureofthe oven, the segment-gear, pinion, and index are returned to theirnormal location by means of a springarm, O, acting on a toggle or arm,I), which connects with the segmentgear.

In the present compact and improved construction of my thermometer thearm Pserves to make an easy and effective connection between the springO and the segment, some such arm being necessary 011 account of thearrangement ofthe numerous parts. A screw, g, passes through the casingand bears against the spring O, thus regulating the degree of its jtension. rlhis spring is made of cast-iron. By

continuous experimenting I have found that cast-iron is the only metalsuitable for the purpose, and I therefore contend, and do hereexplieitely state, that I consider the cast-iron spring for use in thisconnection to be, broadly, my invention and discovery.

Having thus described myinvention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a thermometer, the combination,with e the expansible bars B B BB'" and levers C C C C Ot, of the link D, segment-gear E, pinion F,shaft G, index-finger H, and dialplate, substantially as described.

2. The combination, with the expansible 7 mechanism of a pyrometer, ofthe east-iron spring O, the arm I), segmentfgear E, pinion F, shaft G,indeieinger II, and dial-plate, as specified.

3. In a thermometer, mechanism, the com- 7 bination of the east-ironspring O, having an adjusting-screw, g, the arm I, and the seg ment-gearE, substantially as and for the purposes herein set forth.

4. rlhe combination, with the expansible F bars B B B" B. levers C C C C(1*, link D, segment-gear E, and pinion F, of the castiron spring O andthe arm P, substantially as described.

5. The combination of the casing A, pro- 8 videdinternally with guides ca, the expansible bars B B B" B", supported in said guides, the pivotedlevers C C C" G C4, the screw I1, for adjusting said bars and levers,the pivoted segment-gear E, link D, adjustable cast-iron spring 0, armI, shaft L, the pinion K, and index-finger M, mounted on said shaft, anda dial, It, all arranged to operate substantially as described.

6. In a thermometer, the combination of 9 the cxpansible bars B B B B,levers C C C C 0*, screw b, for adj nsting said bars and levers, thelink I), segment-gear E, pinion F, shaft G, indexringer H, anddial-plate, substantially as described.

7. In an oven-tl1ermometer,the combination of the dial-case, thepyrometer-mechanism case connected with the dial`ease by suitable means,and intervening layers of asbestus, substantially as and for thepurposes shown 1 and described.

8. The combination, of the dial-case, the door J, thepyrometer-mechanism case, connected with the dial-case by screws andhavinga cover, I, provided with tubular projecl tion K, and the layersof asbestus intervening between the two easings, as specified and shown.

9. The combination of the dial-ease, the pyrometer-mechanism caseconnected with the dial-ease by suitable means, andthe interven- 1 ingalternating layers of asbestus and metal, arranged substantially as andfor the purposes described.

In testimony whereof I affix my signature in presence of two witnesses.

DAVID G. COOPER.

lVitnesses:

WM. VON Toner., T. F. HIGGINS.

